*Review* **Gut Microbiota: Implications in Alzheimer's Disease**

**Yixi He 1, Binyin Li 1, Dingya Sun 2 and Shengdi Chen 1,\***


Received: 30 March 2020; Accepted: 15 June 2020; Published: 29 June 2020

**Abstract:** Alzheimer's disease (AD), the most common cause of dementia, is a neurodegenerative disease that seriously threatens human health and life quality. The main pathological features of AD include the widespread deposition of amyloid-beta and neurofibrillary tangles in the brain. So far, the pathogenesis of AD remains elusive, and no radical treatment has been developed. In recent years, mounting evidence has shown that there is a bidirectional interaction between the gu<sup>t</sup> and brain, known as the brain–gut axis, and that the intestinal microbiota are closely related to the occurrence and development of neurodegenerative diseases. In this review, we will summarize the laboratory and clinical evidence of the correlation between intestinal flora and AD, discuss its possible role in the pathogenesis, and prospect its applications in the diagnosis and treatment of AD.

**Keywords:** Alzheimer's disease; gu<sup>t</sup> microbiota; microbiota–gut–brain axis; neurodegenerative disease; intestinal flora
